Noiseless buffer for type-writer escapement.



. .N. H. ANDERSON. NOISELESS BUFFER FOR TYPE WRITER ESCAPEMENT. APPLICATION FILED mm. 31. 1917.

1,250,756., Patented 360,155,191:

'NILS H. Annnnson, or semenronr, CONNECTICUT, assro'non or ONE-HALF To WILLIAM A. Lonnnz, or HARTFORD, CONNECTICUT.

norsnLnss BU-FFE 'FOB. TYPE-WRITER ESCAPEMENT.

To all whom it c' oncern:

Beitknown that I, NiL's H. ANDERSON, a citizen of the United States, residing at Bridgeport, in the county of Fair-field and State of Connecticut, have invented a new and useful Improvement in Noiseless Buffers for Type-Writer Escapements, of which the following is a specification. v

The paper carriageof a typewriting machine is drawn across the frame by a spring tension device with a step by step movement as the space bar or the type or tabulator keys are operated in" writing,an 'escapement mechanism releasing and then. stopping the carriage afterit has moved the required dis tance. This invention relates to the escapeinent mechanism provided for this purpose.

The papercarriagc has a feed rack that is engaged by a pinion which is connected with a toothed escape wheel. Through such connection the escape wheel is subject to the pull of thespring tension device provided for feeding the carriage and consequently tends to turn. Oscillatory feed andstop pawls are arranged to disengage and engage the teeth of the escape wheel as the machine is operated for releasing the escape wheel and allowing the carriage to feed and for holding the escape wheel and stopping the carriage after it has fed. In machines in common use the carriage as it steps from tooth to tooth motes quickly and stops suddenly and this sudden arresting of the momentum of the carriage causes considerable shock and objectionable noise. Theobject of this invention is to provide a buffer for the stop pawl that is constructed and arranged to materially lessen the shock of the blows of the teeth of the escape wheel against the stop pawl and arrest the movement of the carriage less suddenly when it feeds, which butter is so designed that it can be conveniently attached to the present commercial machines without requiring any change in the escape mechanism of such machines and can be used as a speed adjuster.

The invention is illustrated as applied to the well known Underwood typewriting machine, although it is applicable to other makes of machines. elevation, with parts-broken away, of such a machine with a noiseless buffer that,embodies the invention applied to the escape mechanism. Fig. 2 shows on larger scalean elevation of the csca ement rocker which the buffer.

Figure 1 shows a rear Specification of Letters Patent. te t Application filed January 31, '1917. Serial No. 145,579. i

the noiseless buffer is shown as attached.

F ig. 3 is an edge view of the rocker, pawls and buffer. Fig. 4 is a perspective view of In the type of machine shown the paper carriage 1 is drawn across the frame 2 in the direction indicated by the arrow 3 by the usual spring barrel 4 that is connected with the carriage by the band 5. Attached to the underside of the carriage is the feed rack 6 that normally engages with the-pinion 7. .Connected with the pinion is the escape wheel 8. The free end of the stop pawl 9 normally engages a tooth of the escape wheel and holds the wheel against rotation. The stop pawlis pivoted to the escapement rocker 10 which is pivotally mounted on the ends of screw pintles 11 that turn in the stationary uprights 12. a On the upper end bf the escapement rocker is a feed pawl 13. A spring 14' tendsto draw the stop pawllforward and a. fixed stop 15 is provided to limit the backward movement of the stoppawl.

When in-the course of use of the machine the type keys or space bar are operated the escapement rockert'is oscillated to first swing the feed pawl sidewise into the path of a tooth of'the escape wheel and swing the stop pawl sidewise out of engagement with the tooth of the'escape wheel, then the stop pawl-which has been drawn forward by its spring swings sidewise into the path of the next tooth of the escape wheel and the feed pawl swings sidewise out of engage- -ment with the tooth of the escape wheel and allows the wheel to turn and the carriage to feed one space. The blows of the teeth against the stop pawl when the escape wheel turns drive the stop pawl, in the present machines, back againsta fixed stop.. To elimihate the shock and noiseincident to this violent stopping. of the carriage, a yielding buffer member is mounted on the, escapement rocker in position to cushion the stop shown as formed of a plate 16 with a slotted hole 17 for one attachment screw and a slotted notch 18 for another attachmentscrew. A long slot 19 is cut in this plate so as to form an extended spring arm20. This plate is attached to the escapcment rocker in such position that the free end of the spring pawl when it is driven back. This buffer is arm W111 engage the edge of the stop pawl 91/ ,gwheel when the carriage moves to relieve the shock and eliminate the noise and the sudden stopping of the carriage. The slots.

in the buffer plate permit its adjustment up and down so that the spring buffer can be utilized to alter the time of starting of txel carriage.

When the position the stop pawl is retained in st ch relationthat the carriage will not be released until after a type has imprinted its impression on the paper. When the buffervis adjusted to its highest position the stop pawl is retained in such-relation that the carriage will be released just previous to the type striking'tlie paper. By setting the buffer in an intermediate position an intermediate release may be obtained. Previously this adjustment, which is made according to the proficiency of the operator, has been effected by the use of what is known 'as a speed jar -'l spacer. Besides acting to eliminate noise :2 5"

and shook my improved buffer eliminates the use of a speed spacer.

The invention claimed is; 1. The combination in a typewriting machine escapement, of an escapement rocker, a feed pawl carried by said rocker, a stop pawl pivoted on said rocker, and a plate having a resilient arm with its free end adapted to be engaged by the stop pawl during its backward movement, adjustably attachedto said rocker. 2/ The combination in a typewriting ma- .pawl pivoted on said rocker, and a slotted {plate having a yielding arm with it's free end adapted to be engaged by the stop pawl attached to said rocker so the point of engagement of arm and pawl may be varied. 3. The combination in a typewriting m'achine escapement, of an escapementrocker, a feed pawl carried by said rocker, a stop l pawl pivoted on said rockeryand a plate attached to said rocker, said plate having an 1 elongated slot formed therein to provide a yielding arm with its free end adapted to be engaged by the stop pawl during its' backward movement. v

4. The combination in atypewriting -ma'-. chine escapement, of an escapement rocker, a feed pawl carriechby said rocker, a stop pawl pivoted on said'rocker, and a plate attached to said rocker, said plate having an elongated slot formed therein toprovide a yielding arm with its free end adapted to lieengaged by the stop pawl during its backward movement, said plate also being slotted soit may be adjusted to vary the point of engagement of the arm and pawl.

' NILS HsANDERSQN.

I during its backward move adlustablyl bufler is located. at its lowes chine escapement, of an escapement rocker,

- afeed pawl carried by said rocker, a stop 

